collective motion
{{Short description|Spontaneous ordered movement of independent agents}}
Collective motion is defined as the spontaneous emergence of ordered movement in a system consisting of many self-propelled agents. It can be observed in everyday life, for example in flocks of birds, schools of fish, herds of animals and also in crowds and car traffic. It also appears at the microscopic level: in colonies of bacteria, motility assays and artificial self-propelled particles.{{cite journal | last1 = Palacci | first1 = Jeremie | last2 = Sacanna | first2 = Stefano | last3 = Steinberg | first3 = Asher Preska | last4 = Pine | first4 = David J. | last5 = Chaikin | first5 = Paul M. | year = 2013 | title = Living Crystals of Light-Activated Colloidal Surfers | journal = Science | volume = 339 | issue = 6122| pages = 936–940 | doi = 10.1126/science.1230020 | pmid = 23371555 | bibcode = 2013Sci...339..936P | s2cid = 1974474 }}{{cite journal | last1 = Theurkauff | first1 = I. | last2 = Cottin-Bizonne | first2 = C. | last3 = Palacci | first3 = J. | last4 = Ybert | first4 = C. | last5 = Bocquet | first5 = L. | year = 2012 | title = Dynamic clustering in active colloidal suspensions with chemical signaling | journal = Physical Review Letters | volume = 108 | issue = 26| page = 268303 | doi = 10.1103/physrevlett.108.268303 | pmid = 23005020 | arxiv = 1202.6264 | bibcode = 2012PhRvL.108z8303T | s2cid = 4890068 }}{{cite journal | last1 = Buttinoni | first1 = I. | last2 = Bialké | first2 = J. | last3 = Kümmel | first3 = F.|author4-link=Hartmut Löwen| last4 = Löwen | first4 = H. | last5 = Bechinger | first5 = C. | last6 = Speck | first6 = T. | year = 2013 | title = Dynamical clustering and phase separation in suspensions of self-propelled colloidal particles | journal = Physical Review Letters | volume = 110 | issue = 23| page = 238301 | doi = 10.1103/physrevlett.110.238301 | pmid = 25167534 | arxiv = 1305.4185 | bibcode = 2013PhRvL.110w8301B | s2cid = 17127522 }} The scientific community is trying to understand the universality of this phenomenon. In particular it is intensively investigated in statistical physics and in the field of active matter. Experiments on animals,{{cite journal | last1 = Feder | first1 = Toni | year = 2007 | title = Statistical physics is for the birds | journal = Physics Today | volume = 60 | issue = 10| pages = 28–30 | doi = 10.1063/1.2800090 | bibcode = 2007PhT....60j..28F | doi-access = free }} biological and synthesized self-propelled particles, simulations{{Cite journal|title = Onset of Collective and Cohesive Motion|journal = Physical Review Letters|date = 2004-01-15|pages = 025702|volume = 92|issue = 2|doi = 10.1103/PhysRevLett.92.025702|pmid = 14753946|first1 = Guillaume|last1 = Grégoire|first2 = Hugues|last2 = Chaté|arxiv = cond-mat/0401208 |bibcode = 2004PhRvL..92b5702G |s2cid = 37159324}} and theories{{Cite journal|title = Long-Range Order in a Two-Dimensional Dynamical $\mathrm{XY}$ Model: How Birds Fly Together|journal = Physical Review Letters|date = 1995-12-04|pages = 4326–4329|volume = 75|issue = 23|doi = 10.1103/PhysRevLett.75.4326|pmid = 10059876|first1 = John|last1 = Toner|first2 = Yuhai|last2 = Tu|bibcode = 1995PhRvL..75.4326T }}{{Cite journal|title = Modeling collective motion: variations on the Vicsek model|journal = The European Physical Journal B|date = 2008-07-11|issn = 1434-6028|pages = 451–456|volume = 64|issue = 3–4|doi = 10.1140/epjb/e2008-00275-9|language = en|first1 = H.|last1 = Chaté|first2 = F.|last2 = Ginelli|first3 = G.|last3 = Grégoire|first4 = F.|last4 = Peruani|first5 = F.|last5 = Raynaud|bibcode = 2008EPJB...64..451C |s2cid = 49363896| url=https://hal.science/hal-01053505/file/ark%20_67375_VQC-0PQ0L27B-M.pdf }} are conducted in parallel to study these phenomena. One of the most famous models that describes such behavior is the Vicsek model introduced by Tamás Vicsek et al. in 1995.{{cite journal | last1 = Vicsek | first1 = T. | last2 = Czirok | first2 = A. | last3 = Ben-Jacob | first3 = E. | last4 = Cohen | first4 = I. | last5 = Shochet | first5 = O. | year = 1995 | title = Novel type of phase transition in a system of self-driven particles | journal = Physical Review Letters | volume = 75 | issue = 6| pages = 1226–1229 | doi = 10.1103/PhysRevLett.75.1226 | pmid = 10060237 | arxiv = cond-mat/0611743 | bibcode = 1995PhRvL..75.1226V | s2cid = 15918052 }}
Collective behavior of Self-propelled particles
Just like biological systems in nature, self-propelled particles also respond to external gradients and show collective behavior. Micromotors or nanomotors can interact with self-generated gradients and exhibit schooling and exclusion behavior.{{cite journal | last1 = Wang | first1 = W. | last2 = Duan | first2 = W. | last3 = Ahmed | first3 = S. | last4 = Mallouk | first4 = T. | last5 = Sen | first5 = A. | year = 2013 | title = Small power: Autonomous nano- and micromotors propelled by self-generated gradients | journal = Nano Today | volume = 8 | issue = 5| page = 531 | doi = 10.1016/j.nantod.2013.08.009 }} For example, Ibele, et al. demonstrated that silver chloride micromotors, in the presence of UV light, interact with each other at high concentrations and form schools.{{cite journal | last1 = Ibele | first1 = M. | last2 = Mallouk | first2 = T. | last3 = Sen | first3 = A. | year = 2009 | title = Schooling behavior of light-powered autonomous micromotors in water | journal = Angewandte Chemie International Edition | volume = 48 | issue = 18| pages = 3308–12 | doi = 10.1002/anie.200804704 | pmid = 19338004 }} Similar behavior can also be observed with titanium dioxide microparticles.{{cite journal | last1 = Hong | first1 = Y. | last2 = Diaz | first2 = M. | last3 = Córdova-Figueroa | first3 = U. | last4 = Sen | first4 = A. | year = 2010 | title = Light-Driven Titanium-Dioxide-Based Reversible Microfireworks and Micromotor/Micropump Systems | journal = Advanced Functional Materials | volume = 20 | issue = 10| page = 1568 | doi = 10.1002/adfm.201000063 | s2cid = 51990054 }} Silver orthophosphate microparticles exhibit transitions between schooling and exclusion behaviors in response to ammonia, hydrogen peroxide, and UV light.{{cite journal | last1 = Duan | first1 = W. | last2 = Liu | first2 = R. | last3 = Sen | first3 = A. | year = 2013 | title = Transition between collective behaviors of micromotors in response to different stimuli | journal = Journal of the American Chemical Society | volume = 135 | issue = 4| pages = 1280–3 | doi = 10.1021/ja3120357 | pmid = 23301622 | bibcode = 2013JAChS.135.1280D }}{{cite journal | last1 = Altemose | first1 = A. | last2 = Sánchez-Farrán | first2 = M. A. | last3 = Duan | first3 = W. | last4 = Schulz | first4 = S. | last5 = Borhan | first5 = A. | last6 = Crespi | first6 = V. H. | last7 = Sen | first7 = A. | year = 2017 | title = Chemically-controlled spatiotemporal oscillations of colloidal assemblies | journal = Angewandte Chemie International Edition | volume = 56| issue = 27| pages = 7817–7821| doi = 10.1002/anie.201703239 | pmid = 28493638 | doi-access = free }} This behavior can be used to design a NOR gate since different combinations of the two different stimuli (ammonia and UV light) generate different outputs. Oscillations between schooling and exclusion behaviors are also tunable via changes in hydrogen peroxide concentration. The fluid flows generated by these oscillations are strong enough to transport microscale cargo and can even direct the assembly of close-packed colloidal crystal systems.{{Cite journal|last1=Altemose|first1=Alicia|last2=Harris|first2=Aaron J.|last3=Sen|first3=Ayusman|date=2020|title=Autonomous Formation and Annealing of Colloidal Crystals Induced by Light-Powered Oscillations of Active Particles|journal=ChemSystemsChem|language=en|volume=2|issue=1|pages=e1900021|doi=10.1002/syst.201900021|issn=2570-4206|doi-access=free}} Motile emulsions are also known to exhibit emergent, collective behavior.{{Cite journal |last1=Carlsson |first1=Christian |last2=Gao |first2=Tong |date=2024 |title=Active Droplet Driven By Collective Chemotaxis |journal=Soft Matter |volume=20 |issue=48 |pages=9562–9571 |language=en |doi=10.1039/D4SM00717D |issn=1744-683X|doi-access=free }}{{Cite journal |last1=Liu |first1=Yutong |last2=Kailasham |first2=R. |last3=Moerman |first3=Pepijn G. |last4=Khair |first4=Aditya S. |last5=Zarzar |first5=Lauren D. |date=2024-11-07 |title=Self-Organized Patterns in Non-Reciprocal Active Droplet Systems |journal=Angewandte Chemie International Edition |volume=63 |issue=49 |language=en |doi=10.1002/anie.202409382 |issn=1433-7851|doi-access=free |pmid=39321140 |pmc=11586706 }} For example, oil and surfactant combinations can be altered in oil-in-water emulsions, to switch between attractive and repulsive interactions between the droplets.{{Cite journal |last1=Wentworth |first1=Ciera M. |last2=Castonguay |first2=Alexander C. |last3=Moerman |first3=Pepijn G. |last4=Meredith |first4=Caleb H. |last5=Balaj |first5=Rebecca V. |last6=Cheon |first6=Seong Ik |last7=Zarzar |first7=Lauren D. |date=2022-08-08 |title=Chemically Tuning Attractive and Repulsive Interactions between Solubilizing Oil Droplets |url=https://onlinelibrary.wiley.com/doi/10.1002/ange.202204510 |journal=Angewandte Chemie |language=en |volume=134 |issue=32 |doi=10.1002/ange.202204510 |bibcode=2022AngCh.13404510W |issn=0044-8249}} These interactions between the droplets can facilitate formation of dynamic, self-organized patterns.{{Cite journal |last1=Liu |first1=Yutong |last2=Kailasham |first2=R. |last3=Moerman |first3=Pepijn G. |last4=Khair |first4=Aditya S. |last5=Zarzar |first5=Lauren D. |date=2024-11-07 |title=Self-Organized Patterns in Non-Reciprocal Active Droplet Systems |journal=Angewandte Chemie International Edition |volume=63 |issue=49 |language=en |doi=10.1002/anie.202409382 |issn=1433-7851|doi-access=free |pmid=39321140 |pmc=11586706 }}
Micromotors and nanomotors can also move preferentially in the direction of externally applied chemical gradients, a phenomenon defined as chemotaxis. Chemotaxis has been observed in self-propelled Au-Pt nanorods, which diffuse towards the source of hydrogen peroxide, when placed in a gradient of the chemical.{{cite journal | last1 = Hong | first1 = Y. | last2 = Blackmann | first2 = NMK | last3 = Kopp | first3 = ND. | last4 = Sen | first4 = A. | last5 = Velegol | first5 = D. | year = 2007 | title = Chemotaxis of nonbiological colloidal rods | journal = Physical Review Letters | volume = 99 | issue = 17| page = 178103 | doi = 10.1103/physrevlett.99.178103 | pmid = 17995374 | bibcode = 2007PhRvL..99q8103H }} Silica microparticles with Grubbs catalyst tethered to them, also move towards higher monomer concentrations.{{cite journal | last1 = Ravlick | first1 = RA. | last2 = Sengupta | first2 = S. | last3 = McFadden | first3 = T. | last4 = Zhang | first4 = H. | last5 = Sen | first5 = A. | year = 2011 | title = A Polymerization-Powered Motor | journal = Angewandte Chemie International Edition | volume = 50 | issue = 40| pages = 9374–7 | doi = 10.1002/anie.201103565 | pmid = 21948434 | s2cid = 6325323 }} Enzymes also behave as nanomotors and migrate towards regions of higher substrate concentration, which is known as enzyme chemotaxis.{{cite journal | last1 = Sengupta | first1 = S. | last2 = Dey | first2 = KK. | last3 = Muddana | first3 = HS. | last4 = Tabouillot | first4 = T. | last5 = Ibele | first5 = M. | last6 = Butler | first6 = PJ. | last7 = Sen | first7 = A. | year = 2013 | title = Enzyme Molecules as Nanomotors | journal = Journal of the American Chemical Society | volume = 135 | issue = 4| pages = 1406–14 | doi = 10.1021/ja3091615 | pmid = 23308365 | bibcode = 2013JAChS.135.1406S }}{{Cite journal|last1=Mohajerani|first1=Farzad|last2=Zhao|first2=Xi|last3=Somasundar|first3=Ambika|last4=Velegol|first4=Darrell|last5=Sen|first5=Ayusman|date=2018-10-30|title=A Theory of Enzyme Chemotaxis: From Experiments to Modeling|journal=Biochemistry|volume=57|issue=43|pages=6256–6263|doi=10.1021/acs.biochem.8b00801|pmid=30251529|issn=0006-2960|arxiv=1809.02530|s2cid=52816076}} One interesting use of enzyme nanomotor chemotaxis is the separation of active and inactive enzymes in microfluidic channels.{{Cite journal|last1=Dey|first1=Krishna Kanti|last2=Das|first2=Sambeeta|last3=Poyton|first3=Matthew F.|last4=Sengupta|first4=Samudra|last5=Butler|first5=Peter J.|last6=Cremer|first6=Paul S.|last7=Sen|first7=Ayusman|date=2014|title=Chemotactic Separation of Enzymes|journal=ACS Nano|language=EN|volume=8|issue=12|pages=11941–11949|doi=10.1021/nn504418u|pmid=25243599|issn=1936-0851|doi-access=free}} Another is the exploration of metabolon formation by studying the coordinated movement of the first four enzymes of the glycolysis cascade: hexokinase, phosphoglucose isomerase, phosphofructokinase and aldolase.{{Cite journal|last1=Zhao|first1=Xi|last2=Palacci|first2=Henri|last3=Yadav|first3=Vinita|last4=Spiering|first4=Michelle M.|last5=Gilson|first5=Michael K.|last6=Butler|first6=Peter J.|last7=Hess|first7=Henry|last8=Benkovic|first8=Stephen J.|last9=Sen|first9=Ayusman|date=2018|title=Substrate-driven chemotactic assembly in an enzyme cascade|journal=Nature Chemistry|language=En|volume=10|issue=3|pages=311–317|doi=10.1038/nchem.2905|pmid=29461522|bibcode=2018NatCh..10..311Z|issn=1755-4330}}{{Cite book|url=https://books.google.com/books?id=sM-IDwAAQBAJ&q=info:dQi1QnJFIqEJ:scholar.google.com&pg=PA45|title=Metabolons and Supramolecular Enzyme Assemblies|date=2019-02-19|publisher=Academic Press|isbn=9780128170755|language=en}} More recently, enzyme-coated particles and enzyme-coated liposomes{{Cite journal |last1=Somasundar |first1=Ambika |last2=Ghosh |first2=Subhadip |last3=Mohajerani |first3=Farzad |last4=Massenburg |first4=Lynnicia N. |last5=Yang |first5=Tinglu |last6=Cremer |first6=Paul S. |last7=Velegol |first7=Darrell |last8=Sen |first8=Ayusman |date=December 2019 |title=Positive and negative chemotaxis of enzyme-coated liposome motors |url=https://www.nature.com/articles/s41565-019-0578-8 |journal=Nature Nanotechnology |language=en |volume=14 |issue=12 |pages=1129–1134 |doi=10.1038/s41565-019-0578-8 |pmid=31740796 |bibcode=2019NatNa..14.1129S |s2cid=208168622 |issn=1748-3395}} have shown similar behavior in gradients of reactants in microfluidic channels.{{Cite journal|last1=Dey|first1=Krishna K.|last2=Zhao|first2=Xi|last3=Tansi|first3=Benjamin M.|last4=Méndez-Ortiz|first4=Wilfredo J.|last5=Córdova-Figueroa|first5=Ubaldo M.|last6=Golestanian|first6=Ramin|last7=Sen|first7=Ayusman|date=2015-11-30|title=Micromotors Powered by Enzyme Catalysis|journal=Nano Letters|volume=15|issue=12|pages=8311–8315|doi=10.1021/acs.nanolett.5b03935|pmid=26587897|bibcode=2015NanoL..15.8311D|issn=1530-6984}} In general, chemotaxis of biological and synthesized self-propelled particles provides a way of directing motion at the microscale and can be used for drug delivery, sensing, lab-on-a-chip devices and other applications.{{Cite journal|last1=Zhao|first1=Xi|last2=Gentile|first2=Kayla|last3=Mohajerani|first3=Farzad|last4=Sen|first4=Ayusman|date=2018-10-16|title=Powering Motion with Enzymes|journal=Accounts of Chemical Research|volume=51|issue=10|pages=2373–2381|doi=10.1021/acs.accounts.8b00286|pmid=30256612|s2cid=52845451|issn=0001-4842}}
See also
Notes
{{reflist|32em}}
Further references
- {{cite journal | last1 = Bricard | first1 = A. | last2 = Caussin | first2 = J. B. | last3 = Desreumaux | first3 = N. | last4 = Dauchot | first4 = O. | last5 = Bartolo | first5 = D. | year = 2013 | title = Emergence of macroscopic directed motion in populations of motile colloids | url = http://www.nature.com/nature/journal/v503/n7474/full/nature12673.html | journal = Nature | volume = 503 | issue = 7474| pages = 95–98 | doi = 10.1038/nature12673 | pmid = 24201282 | arxiv = 1311.2017 | bibcode = 2013Natur.503...95B | s2cid = 1174081 }}
- {{cite journal | last1 = Vicsek | first1 = T. | last2 = Zafeiris | first2 = A. | year = 2012 | title = Collective motion | url = http://www.sciencedirect.com/science/article/pii/S0370157312000968 | journal = Physics Reports | volume = 517 | issue = 3| pages = 71–140 | doi = 10.1016/j.physrep.2012.03.004 | arxiv = 1010.5017 | bibcode = 2012PhR...517...71V | s2cid = 119109873 }}
External links
- [https://www.theguardian.com/science/2014/jan/13/collective-motion-starlings-sardines-physics Physicists come together to explore mechanics of collective motion] The Guardian, 13 January 2014.
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